1. Field of the Invention
The invention relates to a catalyst unit and, furthermore, relates to an exhaust gas catalytic converter.
2. Description of the Related Art
Exhaust gas catalytic converters for large engines, such as, for example, for internal combustion engines in power plants or marine diesel engines, typically include a plurality of catalyst units, wherein each catalyst unit comprises a non-metallic, in particular ceramic catalyst body constructed of fiber mats, through which exhaust gas flows, and a metallic housing, which in some instances surrounds the catalyst body. The metallic housing of the respective catalyst unit connects the respective catalyst unit to other assemblies of an exhaust gas system of the internal combustion engine in a defined manner, for example for connecting to lines conducting exhaust gas. The ceramic catalyst body of a catalyst unit, which in the case of exhaust gas catalytic converters for large engines comprises a substantially cuboid contour with a substantially rectangular inflow side and a substantially rectangular outflow side, is also called honeycomb and the housing of a catalyst unit is also described as canning. A ceramic catalyst body for a catalyst unit is fixed in the metallic housing of the catalyst unit by at least one bearing mat, which is positioned in a gap between the catalyst body and the housing of the respective catalyst unit. For stationary power plant applications, the catalyst body can be adequately fixed in the housing of the catalyst unit without further special measures by one or more bearing mats. In particular for non-stationary applications, such as, for example, for ship applications or marine applications there is the problem however that the catalyst unit is exposed to oscillations or vibrations, which can result in the catalyst body being dislodged in the respective catalyst unit or that the same is even detached from the housing of the catalyst unit. There is therefore a need for a catalyst unit, in particular for ship applications or marine applications, in which despite the load exposure through vibrations or oscillations the catalyst body of a catalyst unit can be securely held in the housing of the same without the risk of dislocating or detaching the catalyst body.